Preamble
The following information was published on the Fixer Profession Forum, thank you for the invested time and breakdown! Especially Zura!

Time to get started on another guide of "How does it work?"

Topic is how weapon damage is calculated, and specifically how the damage at high attack ratings work.

Note : all of the above calculations are based on Player vs Monster (PvM) combat. In Player vs Player (PvP) combat the damage basicly devided by 2.

⇑

1.0 - The basic damage formula

A note before we get into the math: Nearly all weapons have a maximum benefitial skill (MBS) which is the maximum attack rating (AR) that is included in the calculations.
For example you have an AR of 1000 but the weapon only supports a MBS of 800, all calculations are done with 800. This should not lead you to stop increasing your attack skill, with higher AR you still have a higher chance to hit... or differently said you miss less.

⇑

1.1 - ... for Attack Rating (AR) up to 1000

For attack ratings up to 1000, the damage your weapon does is calculated like this:

Example: Demofixer is using a QL 200 Perennium Beamer with a base damage of 175-425. He has an attack rating of 900 and is running "Greater Nano boost" for a +20 damage bonus. So Demofixer's total damage range when using his Beamer will be:

So vs an unarmored opponent, Demofixer will hit for 589 to 1338 damage on regular shot, with an average of 964 damage. If the target is armored (as most targets surely will be!) then the maximum damage is reduced by 1 point for every 10 points of armor the target has.
Minimum damage is never affected. Lets say the target in the example has 5000 AC. Demofixer would then hit for: 589 to (1338 - 5000/10) = 589 to 838 damage, for an average of 714 damage.

⇑

1.2 - ... for Attack Rating above 1000

Over 1000 attack rating the damage formula is changed. This was done by Funcom with the introduction of Shadowlands to reduce damage output from high level players (especially ones over level 200), so that they still would be somewhat comparable to lower level players. The exact mechanics of the reduction is currently unknown but this is certain:

Only damage for attack rating over 1k is affected by the reduction. The damage you do for the first 1000 points of attack rating stays the same, and the extra damage for your attack rating above 1000 attack rating gets added to that. So, if you have 1050 attack rating, you will always have the potential to do more damage than when you had 1000 attack rating.

I have conducted a test to check how much damage is reduced for Fixers above 1000 attack rating. Test was conducted by recording critical hit damage vs leets and other level 1 backyard nasties (which have basicly zero armor) at various attack rating intervals, all the way up to 2464 attack rating. I tested by using these weapons:

Both guns have 2500 Max Beneficial Skill, thus ensuring that MBS will not screw up the results. Added damage was deducted from all hits, so only the base weapon damage and attack rating should be part of the equations.

Test results:

MTI - Russian Good Day - Deluxe @ QL 200 Base damage: 1-280 (280)

AR

Calculation

Real

Calc above 1k

Real above 1k

Reduction in %

1000

1960

1960

0

0

0 %

1281

2353

2081

394

122

31,0 %

1329

2421

2110

462

151

32,7 %

1350

2450

2122

491

163

33,2 %

1384

2498

2141

539

182

33,8 %

1513

2678

2188

719

229

31,8 %

1636

2850

2225

891

266

29,9 %

1777

3048

2257

1089

298

27,4 %

1897

3216

2278

1257

319

25,4 %

2000

3360

2313

1401

354

25,3 %

2098

3497

2337

1538

378

24,6 %

2220

3668

2439

1709

480

28,1 %

2364

3870

2521

1911

562

29,4 %

2402

3923

2539

1964

580

29,5 %

2464

4010

2561

2051

602

29,4 %

Premium Michael Patriot Ffi 29B @ QL 200 Base damage: 40-175(150)

AR

Calculation

Real

Calc above 1k

Real above 1k

Reduction in %

1000

1138

1138

0

0

0 %

1329

1405

1224

268

87

32,5 %

1350

1422

1231

285

94

33,0 %

1384

1450

1242

313

105

33,5 %

1513

1554

1269

417

132

31,7 %

1636

1654

1291

517

154

29,8 %

1777

1769

1309

632

172

27,2 %

1897

1866

1322

729

185

25,4 %

2000

1950

1346

813

209

25,7 %

2095

2027

1381

890

244

27,4 %

2220

2129

1415

992

278

28,0 %

2364

2246

1463

1109

326

29,4 %

2402

2277

1466

1140

329

28,9 %

2464

2327

1486

1190

349

29,3 %

Legend:Attack rating: The attack rating for each test as show in the Stats window.Calc: The amount of damage the weapon should do at a given attack rating, according to the "below 1k damage formula, as shown above"Real: The actual amount of damage the weapon did at a given attack rating. Every weapon was fired at least twice at each attack rating. If the results varied more shots were done, to rule out any oddball results.Calc a 1k: Calculated damage above 1000 attack rating. I.e. the amount of damage the weapon should do for skill above 1000 attack rating, according to the "below 1k damage formula"Real a 1k: The actual amount of extra damage gained for attack rating above 1000 attack rating.%Reduction: How much the damage above 1000 attack rating was reduced to in percent compared to what the weapon should have done, had the damage formula not been changed at 1k.

The above 1k attack rating damage formula

Using the above "quick and dirty" rule the damage formula for above 1k attack rating is:

If you want a more accurate formula: feel free to insert the % reduction most closely matched to your attack rating from the test result tables above.
Thanks to Sparegris and Craticle who helped by buffing my attack rating for the top end tests.

Comments and observations:

1. A few obvious points first but still worth mentioning. Damage reduction is close to identical for the 2 tested weapons, suggesting that the type of weapon does not influence on how much the damage is reduced. Also, when doing the tests I had plenty of opportunity to swap gear and compare the effectiveness of Add all offence items with pure SMG skill weapons. In regards to damage dealing the 2 values are identical. 100 points of SMG = 100 points of add all offence with regards to the damage dealt.
2. As the test shows, the damage reduction for fixers above 1k attack rating is not linear. The reductions varies from aprox 33% of regular efficiency close to 1k attack rating, down to aprox 25% at 2k attack rating.
3. Strangely enough, the reduction is less severe for attack ratings above the 2k mark - at 2,4k attack rating effectiveness is reduced to aprox 29% - significantly up from the reduction at 2k attack rating. This fact favors weapons with high MBS values, such as the new Alien Kyr'Ozch weapons.
4. If you want to do a quick and dirty approximation of Fixer weapon damage beyond 1k attack rating, assume that attack rating above 1k is about 30% as effective as attack rating below 1k. While not 100% perfect, 30% will give a decent average for all above 1k attack ratings.

⇑

2.0 - Critical damage formula

A critical hit follows the same damage formula, but it always assume you hit for maximum damage with a critical damage bonus added on top of that. The critical damage bonus is the number listen in brackets in the weapon description. Perennium Beamer has 150 points of critical bonus, as show by the description: 175-425 (150). Notice how the critical bonus in not expressed as a damage range, but rather a fixed value? In the damage formula that equals that the critical bonus is not affected by armor. So basically the (150), means that when scoring a critical hit, the Perennium Beamer increases from 175-425 variable damage to a critical hit of (425+150=) 575 damage which may be reduced by armor, but it will never fall below (175+150=) 325 damage minimum, no matter how much Armor the target has. Continuing the above example, when scoring a critical hit Demofixer will hit for: